U.S. patent application number 15/274067 was filed with the patent office on 2017-03-30 for cell evaluation device, method, and program.
This patent application is currently assigned to FUJIFILM Corporation. The applicant listed for this patent is FUJIFILM Corporation. Invention is credited to Takashi WAKUI.
Application Number | 20170089883 15/274067 |
Document ID | / |
Family ID | 58407097 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170089883 |
Kind Code |
A1 |
WAKUI; Takashi |
March 30, 2017 |
CELL EVALUATION DEVICE, METHOD, AND PROGRAM
Abstract
Cell evaluation device includes a first evaluation unit that
evaluates the similarity between cells to be evaluated and cell
species, which are located closer to a non-differentiation side
than the cells to be evaluated are in the process of
differentiation of the cells to be evaluated, as a first
similarity, a second evaluation unit that evaluates the similarity
between the cells to be evaluated and cell species, which are
located closer to a differentiation side than the cells to be
evaluated are in the process of differentiation of the cells to be
evaluated, as a second similarity, and a differentiation progress
calculation unit that calculates the degree of progress of
differentiation of the cells to be evaluated based on the first
similarity and the second similarity.
Inventors: |
WAKUI; Takashi;
(Ashigarakami-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJIFILM Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
FUJIFILM Corporation
Tokyo
JP
|
Family ID: |
58407097 |
Appl. No.: |
15/274067 |
Filed: |
September 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 2035/00891
20130101; G01N 2015/1488 20130101; G01N 35/00722 20130101; G01N
15/1468 20130101; G01N 33/5005 20130101; C12M 41/46 20130101; G01N
2015/1006 20130101 |
International
Class: |
G01N 33/50 20060101
G01N033/50; G01N 35/00 20060101 G01N035/00; C12M 1/34 20060101
C12M001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2015 |
JP |
2015-190861 |
Claims
1. A cell evaluation device, comprising: a first evaluation unit
that evaluates a similarity between cells to be evaluated and cell
species, which are located closer to a non-differentiation side
than the cells to be evaluated are in a process of differentiation
of the cells to be evaluated, as a first similarity; a second
evaluation unit that evaluates a similarity between the cells to be
evaluated and cell species, which are located closer to a
differentiation side than the cells to be evaluated are in the
process of differentiation of the cells to be evaluated, as a
second similarity; and a differentiation progress calculation unit
that calculates a degree of progress of differentiation of the
cells to be evaluated based on the first similarity and the second
similarity.
2. The cell evaluation device according to claim 1, wherein the
differentiation progress calculation unit stores a relationship
between the first similarity and the second similarity in a process
of differentiation of reference cells, which are the same species
as the cells to be evaluated, in advance, and calculates the degree
of progress of differentiation of the cells to be evaluated based
on the relationship between the first similarity and the second
similarity stored in advance and the first similarity and the
second similarity obtained by evaluating the cells to be
evaluated.
3. The cell evaluation device according to claim 2, wherein the
differentiation progress calculation unit shows the relationship
between the first similarity and the second similarity of the
reference cells, which is stored in advance, as a straight line or
a curve on a two-dimensional coordinate space, finds a point on the
straight line or the curve corresponding to the first similarity
and the second similarity of the cells to be evaluated, and
calculates the degree of progress of differentiation of the cells
to be evaluated based on lengths of the straight lines or the
curves partitioned off by the point.
4. The cell evaluation device according to claim 3, wherein the
differentiation progress calculation unit sets a straight line on
the two-dimensional coordinate space based on the first similarity
and the second similarity of the cells to be evaluated, finds an
intersection between the straight line and a straight line or a
curve showing the relationship between the first similarity and the
second similarity stored in advance, divides the straight line or
the curve showing the relationship between the first similarity and
the second similarity stored in advance by the intersection, and
calculates the degree of progress of differentiation of the cells
to be evaluated based on lengths of partitioned-off straight lines
or curves.
5. The cell evaluation device according to claim 4, wherein, in a
case where there is a plurality of intersections between the
straight line based on the first similarity and the second
similarity of the cells to be evaluated and the straight line or
the curve showing the relationship between the first similarity and
the second similarity stored in advance, the differentiation
progress calculation unit selects one of the plurality of
intersections based on a positional relationship with intersections
determined in a previous calculation of the degree of progress of
differentiation.
6. The cell evaluation device according to claim 4, wherein, in a
case where there is a plurality of intersections between the
straight line based on the first similarity and the second
similarity of the cells to be evaluated and the straight line or
the curve showing the relationship between the first similarity and
the second similarity stored in advance, the differentiation
progress calculation unit selects one of the plurality of
intersections based on elapsed time information corresponding to a
point on the straight line or the curve showing the relationship
between the first similarity and the second similarity stored in
advance.
7. The cell evaluation device according to claim 3, wherein the
differentiation progress calculation unit calculates the degree of
progress of differentiation of the cells to be evaluated based on
an angle between an axis on the two-dimensional coordinate space
and a straight line based on the first similarity and the second
similarity of the cells to be evaluated.
8. The cell evaluation device according to claim 3, wherein the
differentiation progress calculation unit determines whether or not
the first similarity and the second similarity of the cells to be
evaluated are included in an allowable range, which is set in
advance on the two-dimensional coordinate space based on the
straight line or the curve showing the relationship between the
first similarity and the second similarity of the reference cells
stored in advance, and evaluates the cells to be evaluated as
abnormal cells in a case where it is determined that the first
similarity and the second similarity of the cells to be evaluated
are not included in the allowable range.
9. The cell evaluation device according to claim 4, wherein the
differentiation progress calculation unit determines whether or not
the first similarity and the second similarity of the cells to be
evaluated are included in an allowable range, which is set in
advance on the two-dimensional coordinate space based on the
straight line or the curve showing the relationship between the
first similarity and the second similarity of the reference cells
stored in advance, and evaluates the cells to be evaluated as
abnormal cells in a case where it is determined that the first
similarity and the second similarity of the cells to be evaluated
are not included in the allowable range.
10. The cell evaluation device according to claim 5, wherein the
differentiation progress calculation unit determines whether or not
the first similarity and the second similarity of the cells to be
evaluated are included in an allowable range, which is set in
advance on the two-dimensional coordinate space based on the
straight line or the curve showing the relationship between the
first similarity and the second similarity of the reference cells
stored in advance, and evaluates the cells to be evaluated as
abnormal cells in a case where it is determined that the first
similarity and the second similarity of the cells to be evaluated
are not included in the allowable range.
11. The cell evaluation device according to claim 6, wherein the
differentiation progress calculation unit determines whether or not
the first similarity and the second similarity of the cells to be
evaluated are included in an allowable range, which is set in
advance on the two-dimensional coordinate space based on the
straight line or the curve showing the relationship between the
first similarity and the second similarity of the reference cells
stored in advance, and evaluates the cells to be evaluated as
abnormal cells in a case where it is determined that the first
similarity and the second similarity of the cells to be evaluated
are not included in the allowable range.
12. The cell evaluation device according to claim 3, further
comprising: a display control unit that plots a position, which is
based on the first similarity and the second similarity of the
cells to be evaluated, in the two-dimensional coordinate space to
display the position on a display unit.
13. The cell evaluation device according to claim 4, further
comprising: a display control unit that plots a position, which is
based on the first similarity and the second similarity of the
cells to be evaluated, in the two-dimensional coordinate space to
display the position on a display unit.
14. The cell evaluation device according to claim 5, further
comprising: a display control unit that plots a position, which is
based on the first similarity and the second similarity of the
cells to be evaluated, in the two-dimensional coordinate space to
display the position on a display unit.
15. The cell evaluation device according to claim 6, further
comprising: a display control unit that plots a position, which is
based on the first similarity and the second similarity of the
cells to be evaluated, in the two-dimensional coordinate space to
display the position on a display unit.
16. The cell evaluation device according to claim 9, wherein the
display control unit plots the straight line or the curve, which
shows the relationship between the first similarity and the second
similarity of the reference cells stored in advance, in the
two-dimensional coordinate space to display the straight line or
the curve on the display unit.
17. The cell evaluation device according to claim 10, wherein the
display control unit plots the straight line or the curve, which
shows the relationship between the first similarity and the second
similarity of the reference cells stored in advance, in the
two-dimensional coordinate space to display the straight line or
the curve on the display unit.
18. The cell evaluation device according to claim 11, wherein the
display control unit plots the straight line or the curve, which
shows the relationship between the first similarity and the second
similarity of the reference cells stored in advance, in the
two-dimensional coordinate space to display the straight line or
the curve on the display unit.
19. A cell evaluation method using the cell evaluation device
according to claim 1, comprising: automatically evaluating a
similarity between cells to be evaluated and cell species, which
are located closer to a non-differentiation side than the cells to
be evaluated are in a process of differentiation of the cells to be
evaluated, as a first similarity; automatically evaluating a
similarity between the cells to be evaluated and cell species,
which are located closer to a differentiation side than the cells
to be evaluated are in the process of differentiation of the cells
to be evaluated, as a second similarity; and automatically
calculating a degree of progress of differentiation of the cells to
be evaluated based on the first similarity and the second
similarity.
20. A non-transitory recording medium storing a cell evaluation
program to execute the cell evaluation method according to claim
19, causing a computer to function as: a first evaluation unit that
evaluates a similarity between cells to be evaluated and cell
species, which are located closer to a non-differentiation side
than the cells to be evaluated are in a process of differentiation
of the cells to be evaluated, as a first similarity; a second
evaluation unit that evaluates a similarity between the cells to be
evaluated and cell species, which are located closer to a
differentiation side than the cells to be evaluated are in the
process of differentiation of the cells to be evaluated, as a
second similarity; and a differentiation progress calculation unit
that calculates a degree of progress of differentiation of the
cells to be evaluated based on the first similarity and the second
similarity.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C.
.sctn.119 to Japanese Patent Application No. 2015-190861, filed on
Sep. 29, 2015. Each of the above application(s) is hereby expressly
incorporated by reference, in its entirety, into the present
application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a cell evaluation device,
method, and a recording medium storing a program for evaluating the
degree of progress of differentiation of cells in the process of
performing the induction of differentiation of cells.
[0004] 2. Description of the Related Art
[0005] Pluripotent stem cells, such as induced pluripotent stem
(iPS) cells or embryonic stem (ES) cells, have the ability to
differentiate into cells of various tissues. Accordingly, since
pluripotent stem cells can be applied in regenerative medicine,
development of medicine, elucidation of disease, and the like,
pluripotent stem cells have been drawing attention.
[0006] In order to obtain desired cells, such as nerve cells or
liver cells, from pluripotent stem cells, induction of
differentiation is performed. However, in order to obtain desired
cells more efficiently, it is important to check to what extent
differentiation has progressed in the process of induction of
differentiation.
[0007] For example, JP2010-181391A has proposed evaluating the
degree of differentiation of cells based on chemical composition
analysis of cells using Raman scattering spectra. JP2009-044974A
discloses capturing an image of cells at two or more different
points in time of a culture period, building a predictive model by
analyzing the image at each point in time, and evaluating the
degree of differentiation of cells at the present time by comparing
the analysis result of the image of cells at the present time with
the predictive model.
SUMMARY OF THE INVENTION
[0008] However, the degree of differentiation evaluated in
JP2010-181391A or JP2009-044974A is an indicator that simply
indicates the degree of differentiation. Accordingly, it is not
possible to ascertain the remaining time until desired cell species
are obtained, that is, the remaining time until the end of the
induction of differentiation, based on only the degree of
differentiation. That is, it is not possible to ascertain to what
extent differentiation has progressed for the entire process of
induction of differentiation from the start of the induction of
differentiation to the end of the induction of differentiation.
[0009] Specifically, in the induction of differentiation, the
degree of the induction of differentiation may differ depending on
a culture method or a cell strain, or the progress of
differentiation with respect to the passage of time may not be
constant. For example, in a case where the degree of
differentiation has changed as shown in FIG. 10, the degree of
differentiation is high at time t1, but has not yet reached the
degree of differentiation at time t2 of the end of the induction of
differentiation. Accordingly, even though more time is required
until the end of the induction of differentiation, this is likely
to be erroneously recognized as the approximate end of the
induction of differentiation. Since this affects the scheduling of
culturing and the like, it is not possible to obtain desired cells
efficiently.
[0010] In addition, there is a method of calculating the
morphological similarity between cells in the process of induction
of differentiation and desired cells and checking the degree of
differentiation from the morphological similarity. However, this
case can also be said to be the same as the case of calculating the
degree of differentiation.
[0011] In view of the aforementioned problems, it is an object of
the invention to provide a cell evaluation device, method, and a
recording medium storing a program capable of checking to what
extent differentiation has progressed for the entire process of
induction of differentiation from the start of the induction of
differentiation to the end of the induction of differentiation.
[0012] A cell evaluation device of the invention comprises: a first
evaluation unit that evaluates a similarity between cells to be
evaluated and cell species, which are located closer to a
non-differentiation side than the cells to be evaluated are in a
process of differentiation of the cells to be evaluated, as a first
similarity; a second evaluation unit that evaluates a similarity
between the cells to be evaluated and cell species, which are
located closer to a differentiation side than the cells to be
evaluated are in the process of differentiation of the cells to be
evaluated, as a second similarity; and a differentiation progress
calculation unit that calculates a degree of progress of
differentiation of the cells to be evaluated based on the first
similarity and the second similarity.
[0013] In the cell evaluation device of the invention described
above, the differentiation progress calculation unit can store a
relationship between the first similarity and the second similarity
in a process of differentiation of reference cells, which are the
same species as the cells to be evaluated, in advance, and
calculate the degree of progress of differentiation of the cells to
be evaluated based on the relationship between the first similarity
and the second similarity stored in advance and the first
similarity and the second similarity obtained by evaluating the
cells to be evaluated.
[0014] In the cell evaluation device of the invention described
above, the differentiation progress calculation unit can show the
relationship between the first similarity and the second similarity
of the reference cells, which is stored in advance, as a straight
line or a curve on a two-dimensional coordinate space, find a point
on the straight line or the curve corresponding to the first
similarity and the second similarity of the cells to be evaluated,
and calculate the degree of progress of differentiation of the
cells to be evaluated based on lengths of straight lines or curves
partitioned off by the point.
[0015] In the cell evaluation device of the invention described
above, the differentiation progress calculation unit can set a
straight line on the two-dimensional coordinate space based on the
first similarity and the second similarity of the cells to be
evaluated, find an intersection between the straight line and a
straight line or a curve showing the relationship between the first
similarity and the second similarity stored in advance, divide the
straight line or the curve showing the relationship between the
first similarity and the second similarity stored in advance by the
intersection, and calculate the degree of progress of
differentiation of the cells to be evaluated based on lengths of
partitioned-off straight lines or curves.
[0016] In the cell evaluation device of the invention described
above, in a case where there is a plurality of intersections
between the straight line based on the first similarity and the
second similarity of the cells to be evaluated and the straight
line or the curve showing the relationship between the first
similarity and the second similarity stored in advance, the
differentiation progress calculation unit can select one of the
plurality of intersections based on a positional relationship with
intersections determined in a previous calculation of the degree of
progress of differentiation.
[0017] In the cell evaluation device of the invention described
above, in a case where there is a plurality of intersections
between the straight line based on the first similarity and the
second similarity of the cells to be evaluated and the straight
line or the curve showing the relationship between the first
similarity and the second similarity stored in advance, the
differentiation progress calculation unit can select one of the
plurality of intersections based on elapsed time information
corresponding to a point on the straight line or the curve showing
the relationship between the first similarity and the second
similarity stored in advance.
[0018] In the cell evaluation device of the invention described
above, the differentiation progress calculation unit can calculate
the degree of progress of differentiation of the cells to be
evaluated based on an angle between an axis on the two-dimensional
coordinate space and a straight line based on the first similarity
and the second similarity of the cells to be evaluated.
[0019] In the cell evaluation device of the invention described
above, the differentiation progress calculation unit can determine
whether or not the first similarity and the second similarity of
the cells to be evaluated are included in an allowable range, which
is set in advance on the two-dimensional coordinate space based on
the straight line or the curve showing the relationship between the
first similarity and the second similarity of the reference cells
stored in advance, and evaluate the cells to be evaluated as
abnormal cells in a case where it is determined that the first
similarity and the second similarity of the cells to be evaluated
are not included in the allowable range.
[0020] The cell evaluation device of the invention described above
can further comprise a display control unit that plots a position,
which is based on the first similarity and the second similarity of
the cells to be evaluated, in the two-dimensional coordinate space
to display the position on a display unit.
[0021] In the cell evaluation device of the invention described
above, the display control unit can plot the straight line or the
curve, which shows the relationship between the first similarity
and the second similarity of the reference cells stored in advance,
in the two-dimensional coordinate space to display the straight
line or the curve on the display unit.
[0022] A cell evaluation method of the invention comprises:
automatically evaluating a similarity between cells to be evaluated
and cell species, which are located closer to a non-differentiation
side than the cells to be evaluated are in a process of
differentiation of the cells to be evaluated, as a first
similarity; automatically evaluating a similarity between the cells
to be evaluated and cell species, which are located closer to a
differentiation side than the cells to be evaluated are in the
process of differentiation of the cells to be evaluated, as a
second similarity; and automatically calculating a degree of
progress of differentiation of the cells to be evaluated based on
the first similarity and the second similarity.
[0023] A recording medium storing a cell evaluation program of the
invention causes a computer to function as: a first evaluation unit
that evaluates a similarity between cells to be evaluated and cell
species, which are located closer to a non-differentiation side
than the cells to be evaluated are in a process of differentiation
of the cells to be evaluated, as a first similarity; a second
evaluation unit that evaluates a similarity between the cells to be
evaluated and cell species, which are located closer to a
differentiation side than the cells to be evaluated are in the
process of differentiation of the cells to be evaluated, as a
second similarity; and a differentiation progress calculation unit
that calculates a degree of progress of differentiation of the
cells to be evaluated based on the first similarity and the second
similarity.
[0024] According to the cell evaluation system, method, and
recording medium storing a program of the invention, the similarity
between the cells to be evaluated and cell species located closer
to the non-differentiation side than the cells to be evaluated are
is evaluated as the first similarity, the similarity between the
cells to be evaluated and cell species located closer to the
differentiation side than the cells to be evaluated are is
evaluated as the second similarity, and the degree of progress of
differentiation of the cells to be evaluated is calculated based on
the first similarity and the second similarity. Since the degree of
progress of differentiation is an indicator that indicates to what
extent differentiation has progressed for the entire process of
induction of differentiation from the start of the induction of
differentiation to the end of the induction of differentiation, the
user can make a schedule for culturing by checking the degree of
progress of differentiation. Therefore, it is possible to obtain
desired cells more efficiently.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a block diagram showing the schematic
configuration of a cell evaluation system using an embodiment of a
cell evaluation device of the invention.
[0026] FIG. 2 is a diagram illustrating a method of calculating the
degree of progress of differentiation.
[0027] FIG. 3 is a flowchart illustrating the operation of the cell
evaluation system using an embodiment of the cell evaluation device
of the invention.
[0028] FIG. 4 is a diagram illustrating a method of determining an
abnormal cell.
[0029] FIG. 5 is a diagram illustrating a case where there is a
plurality of intersections between a curve showing the relationship
between the first similarity and the second similarity of reference
cells and a straight line based on the first similarity and the
second similarity of cells to be evaluated.
[0030] FIG. 6 is a diagram illustrating a case where there is a
plurality of intersections between a curve showing the relationship
between the first similarity and the second similarity of reference
cells and a straight line based on the first similarity and the
second similarity of cells to be evaluated.
[0031] FIG. 7 is a diagram illustrating another method of
calculating the degree of progress of differentiation.
[0032] FIG. 8 is a diagram illustrating still another method of
calculating the degree of progress of differentiation.
[0033] FIG. 9 is a diagram illustrating a method of calculating the
degree of progress of differentiation from three-dimensional
information.
[0034] FIG. 10 is a diagram showing an example of a change in the
degree of differentiation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Hereinafter, a cell evaluation system using an embodiment of
a cell evaluation device, method, and program of the invention will
be described in detail with reference to the diagrams. FIG. 1 is a
block diagram showing the schematic configuration of a cell
evaluation system using a cell evaluation device of the present
embodiment.
[0036] As shown in FIG. 1, the cell evaluation system of the
present embodiment includes a cell imaging apparatus 1, a cell
evaluation device 2, a display device 3, and an input device 4.
[0037] The cell imaging apparatus 1 captures an image of cells in
the process of induction of differentiation. As the cell imaging
apparatus 1, specifically, a phase contrast microscope apparatus, a
bright-field microscope apparatus, a differential interference
microscope apparatus, a fluorescent observation microscope
apparatus, and the like can be used. However, other known
microscope apparatuses may also be used. The cell imaging apparatus
1 includes an imaging device, such as a charge-coupled device (CCD)
sensor or a complementary metal-oxide semiconductor (CMOS) sensor,
and a capture image that has been captured by the imaging device is
output to the cell evaluation device 2 from the cell imaging
apparatus 1.
[0038] As cells to be imaged, for example, there are cells in the
process of induction of differentiation from pluripotent stem
cells, such as iPS cells and ES cells, to mesoderm, cells in the
process of induction of differentiation from neural stem cells to
neurons, cells in the process of induction of differentiation from
liver stem cells to liver cells, cells in the process of induction
of differentiation from pluripotent stem cells to myocardial cells,
and cells in the process of induction of differentiation from
hematopoietic stem cells to red blood cells, lymphocytes, or
platelets. However, cells to be imaged are not limited thereto, and
may be cells in the other processes of induction of
differentiation.
[0039] The cell evaluation device 2 calculates the degree of
progress of differentiation of cells included in a captured image
based on the input captured image. The degree of progress of
differentiation shows to what extent differentiation has progressed
for the entire process of induction of differentiation from the
start of the induction of differentiation to a time when desired
cell species are obtained, that is, to the end of the induction of
differentiation.
[0040] Specifically, the cell evaluation device 2 calculates the
similarity between cells to be evaluated and two cell species, and
calculates the degree of progress of differentiation of cells to be
evaluated based on the similarity between the cells to be evaluated
and the two cell species. The two cell species are cell species
located closer to the non-differentiation side than the cells to be
evaluated are and cell species located closer to the
differentiation side than the cells to be evaluated are in the
process of differentiation of the cells to be evaluated.
[0041] Specifically, as shown in FIG. 1, the cell evaluation device
2 includes a first evaluation unit 20, a second evaluation unit 21,
a differentiation progress calculation unit 22, and a display
control unit 23.
[0042] The cell evaluation device 2 is a computer configured to
include a central processing unit (CPU), a semiconductor memory,
and a storage device such as a hard disk or a solid state drive
(SSD). A cell evaluation program of the present embodiment is
installed in the storage device, and the central processing unit
executes the cell evaluation program to operate the first
evaluation unit 20, the second evaluation unit 21, the
differentiation progress calculation unit 22, and the display
control unit 23 described above.
[0043] The first evaluation unit 20 evaluates the similarity
between the cells to be evaluated and cell species, which are
located closer to the non-differentiation side than the cells to be
evaluated are in the process of differentiation of the cells to be
evaluated, as a first similarity.
[0044] For example, in the case of calculating the degree of
progress of differentiation of cells in the process of
differentiation from pluripotent stem cells to mesoderm, the
similarity between the cells to be evaluated and the pluripotent
stem cells is calculated as the first similarity. In the case of
calculating the degree of progress of differentiation of cells in
the process of differentiation from neural stem cells to neurons,
the similarity between the cells to be evaluated and the neural
stem cells is calculated as the first similarity.
[0045] In the case of calculating the degree of progress of
differentiation of cells in the process of differentiation from
liver stem cells to liver cells, the similarity between the cells
to be evaluated and the liver stem cells is calculated as the first
similarity. In the case of calculating the degree of progress of
differentiation of cells in the process of differentiation from
pluripotent stem cells to myocardial cells, the similarity between
the cells to be evaluated and the pluripotent stem cells is
calculated as the first similarity.
[0046] The first similarity is the morphological similarity between
the cells to be evaluated and cell species on the
non-differentiation side. The first evaluation unit 20 includes a
discriminator of cell species on the non-differentiation side
generated using, for example, a method of machine learning, and
calculates the first similarity by inputting an image of the cells
to be evaluated to the discriminator. A known technique can be used
for the machine learning, and methods, such as a neural network, a
support vector machine, and Adaboost, can be mentioned. For a
method of calculating the morphological similarity, it is possible
to use a known technique.
[0047] The discriminator is generated by machine learning in the
feature quantity space based on various feature quantities. At this
time, in the feature quantity space for learning, multi-dimensional
feature quantities, such as a co-occurrence matrix is used. By the
machine learning, it is possible to find a valid identification
surface.
[0048] The second evaluation unit 21 evaluates the similarity
between the cells to be evaluated and cell species, which are
located closer to the differentiation side than the cells to be
evaluated are in the process of differentiation of the cells to be
evaluated, as a second similarity.
[0049] For example, in the case of calculating the degree of
progress of differentiation of cells in the process of
differentiation from pluripotent stem cells to mesoderm, the
similarity between the cells to be evaluated and the mesoderm is
calculated as the second similarity. In addition, in the case of
calculating the degree of progress of differentiation of cells in
the process of differentiation from neural stem cells to neurons,
the similarity between the cells to be evaluated and the neurons is
calculated as the second similarity.
[0050] In the case of calculating the degree of progress of
differentiation of cells in the process of differentiation from
liver stem cells to liver cells, the similarity between the cells
to be evaluated and the liver cells is calculated as the second
similarity. In the case of calculating the degree of progress of
differentiation of cells in the process of differentiation from
pluripotent stem cells to, the similarity between the cells to be
evaluated and the myocardial cells is calculated as the second
similarity.
[0051] The second similarity is the morphological similarity
between the cells to be evaluated and cell species on the
differentiation side. Similarly to the first evaluation unit 20,
the second evaluation unit 21 includes a discriminator of cell
species on the differentiation side generated using, for example, a
method of machine learning, and calculates the second similarity by
inputting an image of the cells to be evaluated to the
discriminator.
[0052] The differentiation progress calculation unit 22 calculates
the degree of progress of differentiation of the cells to be
evaluated based on the first similarity calculated by the first
evaluation unit 20 and the second similarity calculated by the
second evaluation unit 21. Hereinafter, a method of calculating the
degree of progress of differentiation of the present embodiment
will be described.
[0053] The differentiation progress calculation unit 22 stores the
relationship between the first similarity and the second similarity
in the process of differentiation of cells as a reference (cells
that normally differentiate to become a reference; hereinafter,
referred to as reference cells), which are the same species as the
cells to be evaluated, in advance. Then, based on the relationship
between the first similarity and the second similarity stored in
advance and the first similarity and the second similarity obtained
by evaluating the cells to be evaluated, the degree of progress of
differentiation of the cells to be evaluated is calculated.
[0054] Specifically, the differentiation progress calculation unit
22 shows the relationship between the first similarity and the
second similarity of the reference cells as a straight line or a
curve on the two-dimensional coordinate space. FIG. 2 is an example
showing the relationship between the first similarity and the
second similarity stored in advance as a curve CL. However, the
relationship between the first similarity and the second similarity
may be expressed in a straight line as described above.
[0055] In the two-dimensional coordinate space shown in FIG. 2, a
vertical axis A is an axis showing the first similarity, and a
horizontal axis B is an axis showing the second similarity. In the
present embodiment, a point indicating the first similarity and the
second similarity at the start of induction of differentiation of
reference cells is set as a point Ps on the vertical axis A, and a
point indicating the first similarity and the second similarity at
the end of induction of differentiation of reference cells is set
as a point Pd on the horizontal axis B.
[0056] The differentiation progress calculation unit 22 finds a
point on the curve corresponding to the first similarity and the
second similarity of the cells to be evaluated, and calculates the
degree of progress of differentiation of the cells to be evaluated
based on the lengths of curves partitioned off by the point.
Specifically, as shown in FIG. 2, the differentiation progress
calculation unit 22 sets a straight line L on the two-dimensional
coordinate space by connecting a point P, which is expressed by the
first similarity a and the second similarity b of the cells to be
evaluated, and the origin to each other. Then, the differentiation
progress calculation unit 22 finds an intersection Pg between the
straight line L and the curve CL, and divides the curve CL by the
intersection Pg, and calculates the degree of progress of
differentiation of the cells to be evaluated based on the lengths
of curves CL partitioned off by the intersection Pg.
[0057] For example, in a case where the length of a line between
the intersection Pg and the point Pd is set to L1 and the length of
a line between the point Ps and the point Pd is set to L3, the
degree of progress of differentiation is calculated by L1/L3. In a
case where the length of a line between the point Ps and the
intersection Pg is set to L2, L2/L3 may be calculated as the degree
of progress of differentiation.
[0058] The display control unit 23 displays the captured image of
the cells to be evaluated, which is output from the cell imaging
apparatus 1, on the display device 3. In addition, the display
control unit 23 displays the degree of progress of differentiation
of the cells to be evaluated, which is calculated by the
differentiation progress calculation unit 22, on the display device
3.
[0059] In addition to displaying the degree of progress of
differentiation, the display control unit 23 may display the
coordinate axes shown in FIG. 2 on the display device 3 to plot the
curve CL showing the relationship between the first similarity and
the second similarity of the reference cells or a position (point),
which is based on the first similarity and the second similarity of
the cells to be evaluated, on the coordinate axes.
[0060] The display device 3 (corresponding to a display unit of the
invention) is formed by a liquid crystal display or the like. The
input device 4 is formed by a keyboard, a mouse, or the like. The
display device 3 may also be used as the input device 4 by forming
the display device 3 and the input device 4 using a touch
panel.
[0061] Next, the operation of the cell evaluation system of the
present embodiment will be described with reference to the
flowchart shown in FIG. 3.
[0062] First, cells to be evaluated in the process of induction of
differentiation are placed in the cell imaging apparatus 1, and an
image of the cells to be evaluated is captured (S10).
[0063] The image of cells captured by the cell imaging apparatus 1
is input to the first evaluation unit 20 and the second evaluation
unit 21 of the cell evaluation device 2. Then, the first similarity
is calculated by the first evaluation unit 20, and the second
similarity is calculated by the second evaluation unit 21
(S12).
[0064] Then, the first and second similarities calculated for the
cells to be evaluated are input to the differentiation progress
calculation unit 22, and the differentiation progress calculation
unit 22 calculates the degree of progress of differentiation of the
cells to be evaluated based on the input first and second
similarities (S14). Specifically, a curve showing the relationship
between the first similarity and the second similarity of the
reference cells is set on the two-dimensional coordinate space in
which the vertical axis is set as an axis indicating the first
similarity and the horizontal axis is set as an axis indicating the
second similarity as described above.
[0065] Then, the differentiation progress calculation unit 22 sets
a straight line on the two-dimensional coordinate space by
connecting a point, which is expressed by the first similarity and
the second similarity of the cells to be evaluated, and the origin
to each other, and finds an intersection between the straight line
and the curve. Then, the differentiation progress calculation unit
22 divides the curve by the intersection, and calculates the degree
of progress of differentiation of the cells to be evaluated based
on the lengths of partitioned-off curves.
[0066] The degree of progress of differentiation calculated by the
differentiation progress calculation unit 22 is output to the
display control unit 23, and the display control unit 23 displays
the input degree of progress of differentiation on the display
device 3 (S16).
[0067] According to the cell evaluation system of the embodiment
described above, the similarity between the cells to be evaluated
and cell species located closer to the non-differentiation side
than the cells to be evaluated are is evaluated as the first
similarity, the similarity between the cells to be evaluated and
cell species located closer to the differentiation side than the
cells to be evaluated are is evaluated as the second similarity,
and the degree of progress of differentiation of the cells to be
evaluated is calculated based on the first similarity and the
second similarity. Since the user can make a schedule of culturing
by checking the degree of progress of differentiation, it is
possible to obtain desired cells more efficiently.
[0068] In the cell evaluation system of the embodiment described
above, in a case where the differentiation progress calculation
unit 22 calculates the degree of progress of differentiation of the
cells to be evaluated, an allowable range R for which it can be
regarded that differentiation has normally progressed may be set on
the two-dimensional coordinate space based on the curve CL showing
the relationship between the first similarity and the second
similarity of the reference cells, and it may be determined whether
or not a point expressed by the first similarity and the second
similarity of the cells to be evaluated is included in the
allowable range R, as shown in FIG. 4.
[0069] Then, in a case where it is determined that the point
expressed by the first similarity and the second similarity of the
cells to be evaluated is not included in the allowable range R, the
cells to be evaluated may be evaluated as abnormal cells, and
information indicating that the point expressed by the first
similarity and the second similarity of the cells to be evaluated
is not included in the allowable range R may be displayed on the
display device 3 so that the user is notified of the determination
result. In the case of the example shown in FIG. 4, in a case where
the points expressed by the first similarity and the second
similarity of the cells to be evaluated are a point P.sub.1 and a
point P.sub.2, the cells to be evaluated are evaluated as normal
cells and the degree of progress of differentiation is evaluated.
However, in a case where the point expressed by the first
similarity and the second similarity of the cells to be evaluated
is a point P.sub.3, the cells to be evaluated are evaluated as
abnormal cells, and the degree of progress of differentiation is
not evaluated and the user is notified of the evaluation result
indicating that the cells to be evaluated are evaluated as abnormal
cells.
[0070] In the embodiment described above, in a case where the
differentiation progress calculation unit 22 calculates the degree
of progress of differentiation of the cells to be evaluated, in a
case where the curve CL showing the relationship between the first
similarity and the second similarity of the reference cells is a
shape shown in FIG. 5, a plurality of intersections between the
straight line L and the curve CL based on the first similarity and
the second similarity of the cells to be evaluated are present.
[0071] Thus, in a case where a plurality of intersections are
present, the differentiation progress calculation unit 22 may
select one of the plurality of intersections based on the
positional relationship with intersections determined in the
previous calculation of the degree of progress of differentiation.
For example, as shown in FIG. 5, in a case where intersections
P.sub.4 to P.sub.6 are present, the intersection P.sub.5 is
selected in a case where the intersection determined in the
previous calculation of the degree of progress of differentiation
is P.sub.p since time passes in a direction from the point Ps to
the point Pd in the curve CL.
[0072] The intersection selection method is not limited to the
above method. For example, as shown in FIG. 6, elapsed time
information t.sub.1 to t.sub.11 from the start of the induction of
differentiation may be added and stored for each point on the curve
CL showing the relationship between the first similarity and the
second similarity of the reference cells, elapsed time information
closest to the elapsed time from the start of the induction of
differentiation at the present calculation time of the degree of
progress of differentiation may be searched for among the pieces of
elapsed time information t.sub.1 to t.sub.11, and an intersection
closest to the point to which the elapsed time information has been
added may be selected. For example, in a case where the elapsed
time information closest to the elapsed time from the start of the
induction of differentiation at the calculation time of the degree
of progress of differentiation is t.sub.7, an intersection P.sub.5
closest to the point to which the elapsed time information t.sub.7
has been added is selected.
[0073] In the embodiment described above, the degree of progress of
differentiation is calculated based on the intersections between
the straight line connecting the point P, which is expressed by the
first similarity and the second similarity of the cells to be
evaluated, and the origin to each other and the curve CL showing
the relationship between the first similarity and the second
similarity of the reference cells. However, the method of
calculating the degree of progress of differentiation is not
limited thereto. For example, in a case where the relationship
between the first similarity and the second similarity of the
reference cells is expressed by a straight line SL or expressed by
a curve close to the straight line as shown in FIG. 7, the degree
of progress of differentiation may be calculated based on the angle
of the straight line L, which is based on the first similarity and
the second similarity of the cells to be evaluated, on the
two-dimensional coordinate space.
[0074] Specifically, as shown in FIG. 7, in a case where the angle
between the straight line L connecting the point P and the origin
to each other and the vertical axis (straight line connecting the
point Ps and the origin to each other) is .theta..sub.1 and the
angle between the vertical axis and the horizontal axis (straight
line connecting the point Pd and the origin to each other) is
.theta..sub.3, .theta..sub.1/.theta..sub.3 may be calculated as the
degree of progress of differentiation. In addition, in a case where
the angle between the straight line L connecting the point P and
the origin to each other and the horizontal axis is .theta..sub.2,
.theta..sub.2/.theta..sub.3 may be calculated as the degree of
progress of differentiation.
[0075] In the embodiment described above, a point indicating the
first similarity and the second similarity at the start of
induction of differentiation of the reference cells is set on the
vertical axis A, and a point indicating the first similarity and
the second similarity at the end of induction of differentiation of
the reference cells is set on the horizontal axis B. However,
without being limited thereto, the point indicating the first
similarity and the second similarity at the start of induction of
differentiation of the reference cells may be set as a point Ps
outside the vertical axis A, and the point indicating the first
similarity and the second similarity at the end of induction of
differentiation of the reference cells may be set as a point Pd
outside the horizontal axis B, as shown in FIG. 8.
[0076] In the embodiment described above, the degree of progress of
differentiation is calculated based on the two-dimensional
information of the first similarity and the second similarity.
However, the amount of information used to calculate the degree of
progress of differentiation may be further increased to calculate
the degree of progress of differentiation based on the
three-dimensional information.
[0077] Specifically, as shown in FIG. 9, an A axis indicating the
first similarity, a B axis indicating the second similarity, and a
C axis perpendicular to the A axis and the B axis may be set, and
the C axis may be set as an axis indicating the third
information.
[0078] For example, in the case of calculating the degree of
progress of differentiation of cells in the process of
differentiation from neural stem cells to neurons, the size,
circularity, or brightness of the cells to be evaluated can be used
as the third information. In addition, it is also possible to use
the length or the number of axons of the cells to be evaluated, the
size or the number of dendrites, the size or the number of cell
nuclei, the area or density of white streaks indicating the
boundary of cells, and the like.
[0079] In the case of calculating the degree of progress of
differentiation of cells in the process of differentiation from
liver stem cells to liver cells, the size, circularity, or
brightness of the cells to be evaluated, the size or the number of
cell nuclei, the area or density of white streaks described above,
and the like can be used as the third information.
[0080] In the case of calculating the degree of progress of
differentiation of cells in the process of differentiation from
pluripotent stem cells to myocardial cells, pulsation of the cells
to be evaluated, the area or density of white streaks described
above, and the like can be used as the third information. For the
information of the pulsation of cells, for example, electrodes may
be provided and the electric potential of the cells may be obtained
by measurement, or the amount of variation between two images
captured in time series may be obtained.
[0081] Even in the case of calculating the degree of progress of
differentiation based on the three-dimensional information,
similarly to the method of calculating the degree of progress of
differentiation based on the two-dimensional information, a curve
showing the relationship among the first similarity, the second
similarity, and the third information of the reference cells may be
stored in advance, and the degree of progress of differentiation
may be calculated based on the curve. Specifically, for example, an
intersection between the curve described above and the straight
line based on the first similarity, the second similarity, and the
third information of the cells to be evaluated may be found, and
the degree of progress of differentiation of the cells to be
evaluated may be calculated based on the lengths of curves
partitioned off by the intersection.
[0082] However, in the case of calculating the degree of progress
of differentiation based on the three-dimensional information,
there may be no intersection between the curve acquired based on
the reference cells and the straight line acquired based on the
cells to be evaluated. Therefore, for the curve acquired based on
the reference cells, distribution obtained by adding a margin to
some extent is desirable. In a case where there is no intersection
between the curve acquired based on the reference cells and the
straight line acquired based on the cells to be evaluated, the
degree of progress of differentiation may be calculated based on
the two-dimensional information between the first similarity and
the second similarity.
* * * * *